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Java Articles
Page 335 of 450
How to print the pattern of stars in JShell in Java 9?
JShell is a REPL tool introduced in Java 9 that allows us to execute Java code and getting results immediately. We can evaluate expressions or simple algorithms without creating a new project, compile or build it by using JShell. We can also execute expressions, use imports, define classes, methods, and variables. It is a part of Java 9 JDK but not JRE.We can start JShell session in command-prompt by simply typing jshell. We can use different commands: /exit to quit the JShell session, reset/reload JShell anytime by typing /reset, and /reload, /import to list the imports, etc.In the below example, ...
Read MoreWhat are Compact Strings in Java 9?
Since Java 9, the JVM optimizes strings by using a new feature called Compact Strings. Instead of having a char[] array, a string can be represented as a byte[] array. We can use either UTF-16 or Latin-1 to produce either one or two bytes per character. If JVM detects the string contains only ISO-8859-1/Latin-1 characters, then string uses one byte per character internally.The string can be represented with a compact string or not is detected when the string is created. This feature has enabled by default and switches off using the -XX:-CompactStrings. It doesn't revert to a char[] implementation and ...
Read MoreHow to display all stack frames of the current thread in Java 9?
Stack Walking API can provide a flexible mechanism to traverse and extract information from call stacks that allow us to filter and access frames in a lazy manner. StackWalker class is an entry point to Stack Walking API. The stack trace is a representation of a call stack at a certain point of time in which each element represents a method invocation. It contains all invocations from the start of a thread until the point it’s generated.In the below example, we can print/display all stack frames of the current thread by using StackWalker API.Exampleimport java.lang.StackWalker.StackFrame; import java.lang.reflect.Method; import java.util.List; import java.util.stream.Collectors; public ...
Read MoreWhat is Variable Handle in Java 9?
Variable Handle is a variable or reference to a set of variables, including other components of a static field, non-static fields, and outer array elements in the heap data structure. It means that Variable Handle is similar to the existing Method Handle. It can be represented by using java.lang.invoke.VarHandle class. We can use java.lang.invoke.MethodHandles.Lookup static factory method to create Variable Handle objects. It can also be used to access a single element in the array, and byte[] array.Syntaxpublic abstract class VarHandle extends ObjectExampleimport java.lang.invoke.MethodHandles; import java.lang.invoke.VarHandle; import java.util.Arrays; public class VarHandleTest { public static void main(String ...
Read MoreJava program to calculate the GCD of a given number using recursion
You can calculate the GCD of given two numbers, using recursion as shown in the following program.Exampleimport java.util.Scanner; public class GCDUsingRecursion { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter first number :: "); int firstNum = sc.nextInt(); System.out.println("Enter second number :: "); int secondNum = sc.nextInt(); System.out.println("GCD of given two numbers is ::"+gcd(firstNum, secondNum)); } public static int gcd(int num1, int num2) { if (num2 != 0){ return gcd(num2, num1 % num2); } else{ return num1; } } }OutputEnter first number :: 625 Enter second number :: 125 GCD of given two numbers is ::125
Read MoreJava program to calculate the GCD of a given number using recursion
You can calculate the GCD of given two numbers, using recursion as shown in the following program.Exampleimport java.util.Scanner; public class GCDUsingRecursion { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter first number :: "); int firstNum = sc.nextInt(); System.out.println("Enter second number :: "); int secondNum = sc.nextInt(); System.out.println("GCD of given two numbers is ::"+gcd(firstNum, secondNum)); } public static int gcd(int num1, int num2) { if (num2 != 0){ return gcd(num2, num1 % num2); } else{ return num1; } } }OutputEnter first number :: 625 Enter second number :: 125 GCD of given two numbers is ::125
Read MoreWhat is the importance of the ProcessHandle interface in Java 9?
ProcessHandle interface introduced in Java 9. It allows us to perform actions and check the state of a process that relates. This interface provides the process’s native process ID (pid), start time, accumulated CPU time, arguments, command, user, parent process, and descendants.ProcessHandle interface allows us to perform the following actions.It returns a ProcessHandle.Info containing further information about a processThe Pid of a processIf it is aliveRetrieve a snapshot of the direct children of a processRetrieve a snapshot of all descents of a processRetrieve a snapshot of all currently running processesAllow the process to be destroyedIt returns a CompletableFuture with a ProcessHandle for when the ...
Read MoreJava program to find the permutation when the values n and r are given
Permutation refers a number of ways in which set members can be arranged or ordered in some fashion. The formula of permutation of arranging k elements out of n elements is −nPk = n! / (n - k)!Algorithm1. Define values for n and r. 2. Calculate factorial of n and (n-r). 3. Divide factorial(n) by factorial(n-r). 4. Display result as a permutation.Exampleimport java.util.Scanner; public class Permutation { static int factorial(int n) { int f; for(f = 1; n > 1; n--){ ...
Read MoreJava program to find the permutation when the values n and r are given
Permutation refers a number of ways in which set members can be arranged or ordered in some fashion. The formula of permutation of arranging k elements out of n elements is −nPk = n! / (n - k)!Algorithm1. Define values for n and r. 2. Calculate factorial of n and (n-r). 3. Divide factorial(n) by factorial(n-r). 4. Display result as a permutation.Exampleimport java.util.Scanner; public class Permutation { static int factorial(int n) { int f; for(f = 1; n > 1; n--){ ...
Read MoreJava program to display English alphabets
Following is an example to display English alphabets A to Z. Example public class DisplayingAtoZ { public static void main(String args[]){ char ch; System.out.println("List of alphabets are ::"); for(ch = 'A'; ch <= 'Z'; ch++ ){ System.out.print(ch+" "); } } } Output List of alphabets are :: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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